Water-soluble urea-formaldehydeethylene glycol condensation products and process of producing the same



Patented Aug. 8, 1939 Arm-strum 5 maldehyde' type; particularly intended fdlfillse in aqueous solution for such purposes asiilm form- I The resins produced according to our invention are formed by reacting-urea, formaldehyde and ethylene glycol under special reacting conditions diifer s=widely in its characteristics from any previouslyknowndn the art, particularly in its superior stability, A,

Practically all ofthewater-soluble urea-formaldehyde products "which have been described hithertofore fare f characterized by j the relatively high instability in solution withthe result that in a comparatively, short time white precipitates or gels form, rendering the products useless except for immediate use. By, themethod which we describe usefulurea-formaldehyde products may be prepared and kept stable for long periods of time: The advantagesoftheseproduct's are l obvious! For example, standard.uniform prod- 1 pots can now be made on a] large some and in, an economical fashion-bye, resin'jnanufaeturer and shippedto all parts of the, world insteadof being made on the-"job in smallquantities with varying properties justbefore "using, Furthermore, prior to ouririvehtiori, if anyfil nexpected' delay the *use of *the product "occurred, as inthe case of a shut-down of the factory, the old unstable ureaformaldehyde solutions might spoil before they could be utilized.

byde condensatiommechanism whichtakes place in a slightly-alkalinemediumgis' desirably stabl UREA-Fonmmiimit (swoon;v :tconnnusnrou PRODUCTS, M mocsss 0F PRODUQING" .t Theodorez S- Hodginsi-Yl leti'oit} n'd i vHovey, lleasanjt ltidgegltilch llrawing Application: October-l 8,

sensin 234,03 i

This application ts, continuation-in-part of);

Serial No. 203,148,1iled A n e sss, andcom-f prises a method for improving the"water resist-i iijz'd glycol. a practical ,waythis is accomplished ,by the, simultaneous reactionr, of: 1;, mol, .;of urea We have discovered that the ureaformalde y, formalsiof ethylene and 2 111015 of formaldehydeto form dimethylol urea and 1 mol of formaldehyde and 1 to 2 mols of ethylene glycol to form the ethylene lycol formals, the dimethylolurea and the formals then reacting: to form the stable" complexes which are characterized,particiilarly, by their stability in aqueous solution.

These new stable interaction products obtained by reaction of urea,formaldehyde and of ethylene glycol in the presence of the specific catalysts are not to be confused with theordinary urea g formaldehyde condensationproducts which have i been formed first and the polyhydric alcohol added as a plasticizer afterthe resin has been formed. Such products are, not only quiteunstable alone, but also theaddition of the polyhy dric alcoholi 'tends to cause precipitation to take place eveniearlier than if it were not added.

We have found thatfth'er'e is a very definite and limited 1 range "of coinpositlon which gives resin solutions ofstable keepingoualitiesfwhen the numberofreactingmols of urea, ethylene glycol and of formaldehyde z'are held within the range of 1, 1-5, and13'mols-respectively, there is a very definite:'rangetin which:clear, colorless, useful, stable products having improved water resistance; fg, PbWiflQ -vfillflflfinded by: iran where the water resistance ,is at a minimumand where a characteristic white precipitate forms with varying degrees of rapidity, rendering the productsuseless for commercial exploitation.

'. 1 A few of the points used inlocating this range are derived from the following list, which gives some general examples-ofhow the degree of stability varies withchan'ge in? composition:

m Table :I

We have found that an improvement in (a) water resistance, (b) alcohol resistance can be made by limiting the molecular ratio of ethylene glycol to urea from 1 to 5 and increasing the to bake the final film and a decrease in water resistance of the film is noted.

v ExampleI 243 parts (3 mols) aqueous formaldehyde, 62

processing time from 30 minutes as stated in Serial No. 203,148 o -3 ho s at b i g. parts (1 mol) ethylene glycol, and 5 parts am- The water resistance 01' fi ms contfl ni; monium hydroxide (26% NI'IJ) are placed in a mo s e y e 8 90 Per mol u ea ex nt flask employing a reflux condenser and agitated when baked 1 h ur 1"., and fair when for 5 minutes. The 60 parts urea (1 mol) are baked for 5 minu es F- r. the then added and the mixture heated for 60 minwater resistance of these films is inversely pr utes at boiling. The product is then cooled to Dortlolml t0 the 101ml? of et ylene g yco p esroom temperature. This product is characterent. Whe fil s containing 6 m mols ized by its stability and by resistance to water ethylene l co are e p yed. t e water resistand alcohol when baked at relatively low temance is poor even at the higher baking schedule. peratures, e. g., 30 min. at 250 F.

Considering the system: urea, formaldehyde, and ethylene glycol, according to the general Example? formulas-1 111016 urea. 3 1110165 formaldehyde, The product of Example 1 is made and 0.004- 2 mo e ylene glycol, we have the f l i 0.005 mols phosphoric acid per mol of urea is structural possib l t s: added before cooling to room temperature. V

NHI HNGHzOH This product will bake to a hard, glassy water (A) C|=O+2CH:O+(|J=O and alcohol resistant fi lm even when baked as 1 HNCH'OH low as minutes at 190 F. (87.8 C.)

(dimethylolulea) Emmple 3 011,011 O CH' Same as Example 1, but employing 5 mols $H,OH I ethylene glycol per mol urea. The product is 0011, 0-011, very similar to Example 1 in behavior. onion Example 4 (ethylene glycol hemi-iormal) (dioxolane) CH on Same as Example 3, but employing 0.004-0.005

mols phosphoric acid per mol urea. This prodmen 0 H: not is similar to Example 2 in behavior. 3 cnlo't' nlonfi 00k Example 5 Same as Example 1, but time is 3 hours. (ethylene glycol formal) v Example 6 ggi gfs' gg xfiz f $5 383 take place Same as Example 2, but time is 3 hours.

While we prefer to employ ammonium hydroxcomposition ide as a catalyst, we may use other alkaline catacomposition lysts which are capable of volatilization. The volatile alkaline catalysts are employed in order composition that they may be driven ofl upon the applicacomposltmn 4 tion of heat, so that acid-hardening of the resin The alcohol resistance of these fllms is shown may take place by means of the free formic acid in the following table: (which is present in commercial formaldehyde) Than II Partial immersion in denatured alcohol #1 Condition of film cx- M11101 "spot B k Condition ofiilmbelore Condition of immersed scdtoth a] 111 test (a drop a e mmerslon him (2 days) 2 llndezl'lgssvgatch 1 hour at 300 F Thoroughly converted. Slightly softened, but re- Still hard. 0. K.

' Glass hard. Water covers hardnessu nrewhite and transparmoval from the echo]. cut. at whitened. tlninutesat 250! Hard and partially Soltened, but becomes Sottened,but recovers 0. K.

converted. Water hard ondryingout again. upon removal ironlwhite and transparvapors. Ell Aldf3d rd .0 bite. disease 2' wa mers M nineteen a? K A transparent. uponremoval.

Further, we have found that the addition of 0.004-0005 mols phosphoric acid per mol urea greatly augments the speed of baking and improves the water and alcohol resistance. If larger amounts than 0004-0005 mol HaPO4 per mol urea are employed, the stability of the resulting product is but 24-28 hours at 65 C. or about 7-14 days at room temperatures which is =very undesirable for an industrial product. On

the other hand, when smaller amounts are emplayed, much higher temperatures are required remaining after decomposition of ammonium formate which is the salt of a weak acid and I weak base.

The process described in the examples is very simple and automatic-and does not require elaborate and expensive pH control apparatus.

On accountoi their transparency, water-white color, heat-hardening characteristics, and nontoxicity, materials prepared according to our examples are very desirable for coating and sizing paper, for preparing molded and laminated articles, for rendering fabrics more greaseprooi, more creaseproot and increasing the tensile strength. This is especially true of upholstery cloth for automobiles and furniture, wearing apparel, etc.

We claim- '1. A process of preparing a water-soluble, water-white heat-convertible, resinous product characterized by stability in solution, and when baked being characterized by resistance to water and alcohol; which process comprises simultaneously reacting urea, ethylene glycol and formaldehyde for 1-3 hours at boiling temperature employing a ratio of 11-5 mols ethylene glycol per 1 mol urea. and 3 mols aqueous formaldehyde. employing an alkaline catalyst in the initial stage and adding 0.004-0.005 mols phosphoric acid in the flnalstage.

2. A process for preparing a water-soluble, water-white heat-convertible, resinous product characterized by stability in solution, and when baked being characterized by resistance to water and alcohol: which process comprises simultaneously reacting urea, ethylene glycol and formaldehyde in the proportions of 1 mol urea, 1-5 mols ethylene glycol and 3 mols of formaldehyde.

3. A process or preparing a water-soluble, water-White heat-convertible resinous product characterized by stability in solution. and. when baked being characterized by resistance to water and alcohol, which process comprises simultaneously reacting urea, ethylene glycol and formaldehyde in the proportions of 1 mol urea, 1-5 mols ethylene glycol and 3 mols aqueous formaldehyde, in the presence of an alkaline catalyst, and subsequently neutralizing the catalyst.

4. A process of preparing a water-soluble, water-white heat-convertible resinous product characterized by stability in solution, and when baked being characterized by resistance to water and alcohol, which process comprises simultaneously reacting urea, ethylene glycol and formaldehyde for 1-3 hours at boiling temperature, in the proportions of 1 mol of urea, 1-5 mols-ethylene glycol and 3 mols aqueous formaldehyde, employing an alkaline catalyst in the initial stage and subsequently neutralizing the catalyst.

5;. A water-soluble water-white heat-convertible resinous product produced according to claim 2, and having good water resistancewhen baked for one hour at 300 F. and fair water resistance when baked for approximately five minutes at 250 F.

THEODORE S. HODGINS.

ALMON G. HOVEY. 

